Measuring syringe

ABSTRACT

A measuring syringe having an elongated plastic body including a narrow elongated passage opening into one end of the body which removably receives a hollow disposable tip for drawing and expelling a liquid into the tip by means of an elongated piston slidable in the passage. A second enlarged passage in the upper body section which opens into the opposite end of the body slidably receives an actuating stem whose bottom is connected to the piston and whose top projects from the body and is provided with an apertured flange for finger operation. A predetermined quantity of liquid may be drawn and expelled; the quantity being measured by stop members projecting from the actuating stem to be engageable with a stop surface on the body in the second passage. During manufacture, the stem is formed with a plurality of stops spaced along its length and corresponding to different quantities of liquid to be measured. To accomodate the stop members, an elongated slot is formed through one side wall of the body which receives the stop members and also provides visibility thereto.

United States Patent Tejera 1 51 July 11, 1972 [73] Assignee:Mnlllnckrodt Chemical Works, St. Louis,

[22] Filed: June 10,1970

[2|] Appl.No.: 45,133

Primary Examiner-S. Clement Swisher Attorney-Knenig, Senniger, Powers &beavitt [57] ABSTRACT A measuring syringe having an elongated plasticbody including a narrow elongated passage opening into one end of thebody which removably receives a hollow disposable tip for drawing andexpelling a liquid into the tip by means of an elongated piston slidablein the passage. A second enlarged passage in the upper body sectionwhich opens into the opposite end of the body slidably receives anactuating stem whose bottom is connected to the piston and whose topprojects from the body and is provided with an apertured flange forfinger operation. A predetermined quantity of liquid may be drawn andexpelled; the quantity being measured by stop members projecting fromthe actuating stem to be engagesble with a stop surface on the body inthe second passage. During manufacture, the stem is formed with aplurality of stops spaced along its length and corresponding todifferent quantities of liquid to be meuured. To accomodate the stopmembers, an elongated slot is formed through one side wall of the bodywhich receives the stop members and also provides visibility thereto.

w m m m m w /v/ w V E?///// INVENTOR LUIS H, TEJERA Fig. 3.

M M ATTORNEY.

P'A'TENTEDJUL 1 1 1972 Fig. 6 b.

F ig. 6a.

MEASURING svanvcr:

BACKGROUND OF THE INVENTION This invention relates to a syringe and,more particularly, to a measuring syringe suitable for drawing anddispensing predetermined quantities of a liquid.

Many analytical laboratory procedures involve the obtaining and deliveryof small, predetermined quantities of a fluid. For example, in preparingexact dilutions for hematologic and blood chemistry tests, it isextremely important that an accurate volume of blood or serum betransferred to the diluent fluid. In this respect various types ofmeasuring pipettes have been proposed for use in such applications. Ingeneral, simple stem pipettes, calibrated to a mark, have been mostpopular, due probably to disadvantages inherent in the other types notthe least of which is expense. The degree of precision andreproducibility obtained with stem pipettes, however, is severelyhampered by unavoidable slight variations inherent when attempting todraw fluid samples visually to a mark.

The various blood analysis procedures of a typical test series requiredifferent precise quantities of serum or other reagents. In response tothis need (as well as the desire to eliminate the disadvantages of stempipettes) attempts have been made to develop a single measuring syringewhich is mechanically adjustable to obtain and discharge differentamounts of fluid. Such devices are generally complex as they employmechanisms such as springs, gears, and movable set-screws to effectcapacity changes. The relative expense of such devices leads to problemsof maintenance and cleaning since disposal is impractical. Also,mechanisms of even slight complexity have a marked tendancy for foulingas caused by either mechanical failure or operator error.

Accordingly, it is an object of the present invention to provide aninexpensive accurate measuring syringe which may be quickly and easilyoperated and which is of compact construction.

SUMMARY OF THE INVENTION The present invention is directed to ameasuring syringe having an elongated plastic body including a verynarrow elongated passage extending in the lower section thereof andopening into one end of the body for drawing and expelling a liquid intoa hollow disposable tip received on said one end of the body. Slidablein the passage is an elongated needle-like piston which is actuated bymeans of a stem slidable in a second passage extending coaxially withthe first passage in the upper section of the body and opening into theopposite end thereof. Both passages are generally cylindrical; however,the stem-receiving passage has a larger diameter and terminates in ashoulder situated at the upper end of the piston passage. To insure thatthe body passages are sealed from each other at all times an annularsealing ring is seated in a recess in the body between the piston andstem passages for sealingly receiving and engaging the piston.

The valve actuating stem is manipulated for operating the syringe bymeans of an apertured flange formed on the top of the stern externallyof the body. In the lowermost position of the stem and piston theapertured flange rests on the top end of the syringe body. To furtherfacilitate manipulation of the syringe in operation, a pair of concavesurfaces are formed in opposite side walls of the body just below theupper end thereof.

Predetermined quantities of liquid may be drawn into and expelled fromthe syringe by employing one or more stop members formed on the stem asindicators of the various predetermined quantities. The stop memberswhich, in one embodiment, are three in number, project laterally fromthe stem at spaced locations along the same side thereof so as to beengageable with a stop surface formed on the body adjacent to the stempassage at the upper end of the body. Upon movement of the stern throughthe body during use of the syringe, as a selected stop member engagesthe fixed stop surface on the body, the user will know that the desiredpredetermined quantity has either been withdrawn or expelled.

To facilitate movement of the stop members in the stem passage, the bodyis provided with an elongated slot extending generally coextensivelywith the stem passage for receiving the stop members. In the specificembodiment, this slot extends laterally completely through the side wallof the body so as to provide visible access to the stop members.

Other objects and advantages of the present invention will becomereadily apparent from the following more detailed description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of asyringe embodying the present invention.

FIG. 2 is an end view of the syringe shown in FIG. 1 however with thetwo parts thereof removed from each other and with one of the partsshown in cross section.

FIG. 3 is a view similar to FIG. 2 however with the parts in assembledrelationship and with a removable tip employed during use of thesyringe.

FIG. 4 is an enlarged cross sectional view taken generally along lines4-4 of FIG. 1.

FIG. 5 is an enlarged detailed view of a portion of the syringe shown inFIG. 2.

FIGS. 60 and 6b are enlarged, fragrnental cross sectional viewsillustrating a stop feature incorporated in the syringe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingsin detail, there is shown a measuring syringe embodying the inventionand including an elongated body generally designated 10 which may beformed from any suitable plastic material which is inert to the liquidto be handled. Body 10 has an elongated very narrow cylindrical passage12 extending throughout the lower half section thereof and opening intoa nozzle 14 at the lower end of body 10 adapted to removably receive ahollow conical disposable tip 15. Passage 12 is employed to draw liquidinto tip 15 (FIG. 3) and subsequently expel it by means of a plunger orpiston 16 slidably received in passage 12.

Piston 16 is needle-like, being extremely narrow in cross dimension, andhaving a length generally equal to the length of passage 12 while alsohaving a cylindrical shape terminating in a rounded tip 18 at the lowerextremity thereof. The diameter of piston 16 in relation to that of thepiston passage 12 is such that it has a sliding sealing fit therein soso as to create a suction or vacuum in passage 12 when fully inserted inpassage 12 for purposes of subsequently lifiing or drawing liquid intotip 15 upon withdrawal of the piston in the well known manner. Piston 16may be made from the same plastic material as body 10.

Manual actuation of piston 16 for drawing or dispensing a liquid isachieved through an actuating stem 18 which is slidably received in asecond passage 20 in the body formed coaxially with piston passage 12 inthe upper section of the body and opening into the top of the body at22. Actuatingstem passage 20 has a generally cylindrical cross-section,being larger than piston passage 12; the actuating stem 18 also beinglarger than piston 16 so as to be guided by the internal side walls ofpassage 20 during actuation. The lower end of actuating stem 18 isconnected to the upper end of piston 16, with the surface 24 on thebottom of the actuating stem around the piston 16 forming a shoulderwhich abuts against an internal shoulder 26 formed in the body betweenthe upper and lower passages 20 and 12, when the actuating stem is inits lowermost position in the body.

Finger manipulation of the operating stern for operating the syringe isobtained by an enlarged apertured flange 28 formed on the top ofactuating stem 18 to comfortably receive the finger of the user. Thebottom surface of flange 28 is elliptical in shape to correspond withthe shape of the top surface 21 of the body on which the flange restswhen the stem and piston are fully inserted in the body. The actuatingstem may also be made from a suitable plastic and with an integralconstruction.

To insure that the piston passage 12 and the stem passage 20 are sealedfrom each other, an annular sealing ring 30 of any suitable material isprovided in the body to sealingly engage piston 16. For this reason, theinternal diameter of sealing ring 30 is less than the diameter of piston16 to insure a good seal. in the specific form illustrated, sealing ring30 is placed in a recess 32 in the body just above the top end of pistonpassage 12 and below shoulder 26 in the body. The curvature of recess 32conforms to that of sealing ring 30 to insure proper seating of thesealing ring.

In order to permit drawing and dispensing predetermined amounts ofliquid, actuating stem 18 is manufactured with a plurality of stops 40projecting laterally from the stem at axially spaced locationspreferably on the same side thereof, to be engageable with a fixed stopsurface 42 formed in stem passage 20 at the upper end thereof. Dependingon the specific liquid desired to be handled, two of the stops can beremoved, if desired, preferably during manufacture of the syringe, thusleaving one stop corresponding to the desired quantity of liquid to behandled. Subsequently as the stem is fully inserted in the body, thedesired predetermined quantity of liquid will be dispensed from tip 15.in one specific manufacture, three stops 40 are spaced along actuatingstem 18 so as to be able to dispense amounts such as 0.1, 0.5, and 0.02ml as desired. Because stops 40 are slightly resilient due to theirplastic construction, they will pass the stop surface 42 upon insertionof the stem into the body. However, to minimize friction and facilitateinsertion of actuating stem 18 into the body, stops 40 are formed with adownwardly and inwardly inclined surface 44 as shown in FIG. 6.

Movement of stops 40 in the body is permitted by an elongated slot 46formed in one side wall of the upper body section for receiving andaccomodating stops 40 throughout their movement in the body. In thespecific embodiment illustrated, the fixed stop surface 42 is formed bythe upper edge of elongated slot 46. To further reduce friction, theupper portion of stem passage 20 adjacent end 22 may be enlarged such asindicated at 48 (FIG. 6) for receiving the stops before they pass fixedbody stop 42 during movement of the stem into the body. Inasmuch aselongated slot 46 extends entirely through the body sidewall, it alsoprovides visibility to the stops 40.

In the preferred embodiment shown, about three-quarters of the length ofthe body has a conical external shape tapering towards the nozzle end 14which moreover is formed with a reduced external dimension asillustrated. The upper section of body has a generally ellipticalcurvature, except for two opposite concave recesses 50 which are formedto accomodate the fingers of the user.

in the above description, the syringe can be employed with only a singlestop 40 for measuring a single quantity of liquid, the other stopshaving been removed after selection of a desired quantity of liquid.Applicant wishes it understood, though, that the other stops need not beremoved and that the same syringe may be employed to handle any one of aplurality of predetermined quantities of liquids. In this latterinstance, the lateral dimensions of stops 40 are chosen to permit themto be snapped past stop surface 42 upon withdrawal of the actuatingstem. Moreover, although three stops 40 have been shown and described, agreater or lessor number may be employed. Also, although the syringe hasbeen described above for use in conjunction with a disposable tip 15,the invention may also be utilized without such a tip.

it will be understood that in using the syringe, the stem 18 is pulledout to the limit determined by engagement of the stop 40 in slot 46farthest from shoulder 26 (the middle stop of the three shown in FIGS. 1and 3) with the end at 42 of the slot 46 for an intake stroke of theplunger or piston 16 thereby to prime the passage 12 (including the tipif the latter is used) with a measured quantity of liquid as determinedby the intake stroke. Then, the stem is pushed in for a discharge strokeof the plunger or piston 16 to the limit determined by engagement of theinner end 24 of the stem with the shoulder 26.

What is claimed is:

l. A measuring syringe comprising: a body having a first, narrow,elongated passage in one end thereof extending longitudinally of thebody, a second passage extending longitudinally in the body above saidfirst passage and having a greater width than said first passage; apiston assembly including an elongated narrow piston slidably receivedin said first passage for drawing and expelling liquid, an actuatingstem connected to said piston at one end and slidably received in saidsecond passage for operating the piston upon longitudinal movement ofthe stem; stop means in said body at a particular position along saidsecond passage; and a plurality of stop members projecting laterallyfrom the stem at locations spaced axially along the stern to besuccessively engageable with said stop means upon withdrawal of the stemto measure the amount of liquid drawn into said first passage wherebypredetermined amounts of liquid may be drawn and subsequently expelledfrom said first passage, the stop means and the stop member beingconstructed relative to each other to provide for an insertion of thepiston into the body in one direction to obtain a movement of the stopmembers past the stop means and to inhibit the withdrawal of the stopmembers past the stop means in the other direction, and wherein saidbody has an elongated slot in one sidewall thereof communicating withsaid second passage and extending to said stop means to provide for thepassage of said stop members along said body.

2. A syringe as defined by claim 1 wherein said stop members are locatedin substantially aligned relationship on the same side of said stop.

3. A measuring syringe comprising in combination: a body having a first,narrow elongated passage in one end thereof extending longitudinally ofthe body, a second passage extending longitudinally in the body inalignment above said first passage and having a greater cross-dimensionthan said first passage; a piston assembly including an elongated narrowpiston slidably received in said first passage for drawing and expellingliquid, an actuating stem extending longitudinally from said piston atone end and slidably received in said second passage for operating thepiston upon longitudinal movement of said stem, said actuating stembeing dimensioned to be slidably engageable with internal surfaceportions of said body to be guided thereby during sliding movement ofthe actuating stern in .the body; stop means formed in said body at aparticular position along said second passage; and a stop memberprojecting laterally from the stem to be engageable with said stop meansupon withdrawal of the stem longitudinally along the second passage toinhibit further withdrawal of said stem and to provide for apredetermined amount of said liquid to be drawn and expelled with theuse of the syringe, and wherein said body has a longitudinally extendingelongated slot in a wall of said second passage for receiving said stopmember and for providing for a movement of said stern longitudinallyalong said passage.

4. A syringe as defined by claim 3 wherein said body has the stop meansin communication with said slot and wherein said stop means isconstructed to provide for a longitudinal inser-- tion of said sterninto said body to obtain the movement of said stop members past saidstop means and to inhibit the longitudinal withdrawal of said stem fromsaid body to a position where die stop member would be withdrawn pastsaid stop means.

5. A syringe as defined by claim 4 wherein said actuating stem projectsfrom the outer end of said body and has an apertured flange fixed to theouter end thereof and adapted to engage on said other end of the bodywhen the stem is fully inserted in the body.

6. A syringe as defined by claim 5 wherein said body has an upperportion surrounding a portion of said second passage and having agenerally elliptical transverse curvature in the periphery thereof, saidbody portion also having in the opposite ends thereof external concaverecesses for accomodating the fingers of an operator.

7. A syringe as defined by claim 6 wherein said body has a secondportion surrounding said first passage and having a generally conicalcross-section which converges from said upper portion towards said oneend of the body.

8. A syringe as defined by claim 4 wherein said stop member is formedfrom a resilient material to facilitate the longitudinal movement of thestop member past said stop means during insertion of the stern into thebody.

9. A syringe as defined by claim 4 wherein said piston and stemincluding said stop member are integral with each other and formed fromplastic material.

10. A syringe as defined by claim 4 wherein said stop means is formed atthe upper edge of said elongated slot.

11. A syringe as set forth in claim 4 wherein the second passage in thebody is enlarged at the end thereof away from the first passage.

12. A measuring syringe comprising in combination: a body having afirst, narrow, elongated passage in one end thereof extendinglongitudinally of the body, a second passage extending longitudinally inthe body in alignment above said first passage and having a greatercross-dimension than said first passage; a piston assembly including anelongated narrow piston slidably received in said first passage fordrawing and expelling liquid, an actuating stem connected to said pistonand slidably received in said second passage for operating the pistonupon longitudinal movement of said stem, said actuating stem beingdimensioned to be slidably engageable with internal surface portions ofsaid body to be guided thereby during sliding movement of the actuatingstern in the body; stop means formed in said body adjacent said secondpassage; and a stop member projecting laterally from the stem to beengageable with said stop means upon withdrawal of the stem to measure apredetermined amount of said liquid to be drawn and expelled with theuse of the syringe, said actuating stem projecting from the outer end ofsaid body and having an apertured flange fixed to the outer end thereofand adapted to engage on said other end of the body when the stem isfully inserted in the body, said stop member being formed from aresilient material to enable the stop member to pass said stop meanduring assembly, said stop member having an inclined outer surfaceslanting inwardly toward the piston end of the stem.

13. A measuring syringe comprising: a body having a first, narrow,elongated passage in one end thereof extending longitudinally of thebody, a second passage extending longitudinally in the body above saidfirst passage; a piston assembly including an elongated narrow pistonslidably received in said first passage for drawing and expellingliquid, an actuating stem connected to said piston and slidably receivedin said second passage for operating the piston upon longitudinalmovement of the stem; stop means in said body adjacent said secondpassage; and a plurality of stop members projecting laterally from thestem at locations spaced axially along the stem to be successivelyengageable with said stop means upon withdrawal of the stem to measurethe amount of liquid drawn into said first passage whereby predeterminedamounts of liquid may be drawn and subsequently expelled from said firstpassage, said stop members made from resilient material to enable thestop members to pass said stop means, and said stop members having outersurfaces inclined inwardly towards the piston end of the stem.

14. A measuring syringe comprising an elongate body hav ing a firstlongitudinal passage extending inwardly from one end thereof and asecond longitudinal passage of larger cross section than the firstpassage in line with the first passage and extending from the inner endof the first passage through the body to its other end with a shoulderat the inner end of the second passage around the inner end of the firstpassage, said body having a longitudinal slot in one side thereofopening into said second longitudinal passage, an elongate actuatingstern having a sliding fit in the second passage extending out of saidother end of said body and having means at its outer end enabling it tobe manually pulled out a plunger extending from the inner end of saidstem through the first passage an having a sliding sealing fit therein,said stem having an integral stop projecting laterally outwardly intosaid slot, the stern being adapted to be pulled out to the limitdetermined by engagement of the stop with the end of the slot towardsaid other end of the body for an intake stroke of said plunger therebyto prime said first passage with a measured quantity of liquid, and thenpushed in for a discharge stroke of the plunger to the limit determinedby engagement of the inner end of the stem with said shoulder.

15. A measuring syringe as set forth in claim 14 wherein said stem isformed with a plurality of integral stops spaced at intervals along itslength, each of the stops being adapted to be snapped past said otherend of the body.

16. A measuring syringe comprising: a body having a first, narrow,elongated passage in one end thereof extending longitudinally of thebody, a second passage extending longitudinally in the body above saidfirst passage and having a greater width than said first passage; apiston assembly including an elongated narrow piston slidably receivedin said first passage for drawing and expelling liquid, an actuatingstem connected to said piston at one end and slidably received in saidsecond passage for operating the piston upon longitudinal movement ofthe stem; stop means in said body at a particular position along saidsecond passage; and a plurality of stop members projecting laterallyfrom the stem at locations spaced axially along the stem to besuccessively engageable with said stop means upon withdrawal of the stemto measure the amount of liquid drawn into said first passage wherebypredetermined amounts of liquid may be drawn and subsequently expelledfrom said first passage, the stop means and the stop member beingconstructed relative to each other to provide for an insertion of thepiston into the body in one direction to obtain a movement of the stopmembers past the stop means and to inhibit the withdrawal of the stopmembers past the stop means in the other direction, and wherein saidbody has an elongated slot in one sidewall thereof communicating withsaid second passage and extending to said stop means to provide for thepassage of said stop members along said body, and wherein said stopmembers are located in substantially aligned relationship on the sameside of said stop, and wherein the second passage in the body isenlarged at the end thereof away from the first passage.

1. A measuring syringe comprising: a body having a first, narrow,elongated passage in one end thereof extending longitudinally of thebody, a second passage extending longitudinally in the body above saidfirst passage and having a greater width than said first passage; apiston assembly including an elongated narrow piston slidably receivedin said first passage for drawing and expelling liquid, an actuatingstem connected to said piston at one end and slidably received in saidsecond passage for operating the piston upon longitudinal movement ofthe stem; stop means in said body at a particular position along saidsecond passage; and a plurality of stop members projecting laterallyfrom the stem at locations spaced axially along the stem to besuccessively engageable with said stop means upon withdrawal of the stemto measure the amount of liquid drawn into said first passage wherebypredetermined amounts of liquid may be drawn and subsequently expelledfrom said first passage, the stop means and the stop member beingconstructed relative to each other to provide for an insertion of thepiston into the body in one direction to obtain a movement of the stopmembers past the stop means and to inhibit the withdrawal of the stopmembers past the stop means in the other direction, and wherein saidbody has an elongated slot in one sidewall thereof communicating withsaid second passage and extending to said stop means to provide for thepassage of said stop members along said body.
 2. A syringe as defined byclaim 1 wherein said stop members are located in substantially alignedrelationship on the same side of said stop.
 3. A measuring syringecomprising in combination: a body having a first, narrow elongatedpassage in one end thereof extending longitudinally of the body, asecond passage extending longitudinally in the body in alignment abovesaid first passage and having a greater cross-dimeNsion than said firstpassage; a piston assembly including an elongated narrow piston slidablyreceived in said first passage for drawing and expelling liquid, anactuating stem extending longitudinally from said piston at one end andslidably received in said second passage for operating the piston uponlongitudinal movement of said stem, said actuating stem beingdimensioned to be slidably engageable with internal surface portions ofsaid body to be guided thereby during sliding movement of the actuatingstem in the body; stop means formed in said body at a particularposition along said second passage; and a stop member projectinglaterally from the stem to be engageable with said stop means uponwithdrawal of the stem longitudinally along the second passage toinhibit further withdrawal of said stem and to provide for apredetermined amount of said liquid to be drawn and expelled with theuse of the syringe, and wherein said body has a longitudinally extendingelongated slot in a wall of said second passage for receiving said stopmember and for providing for a movement of said stem longitudinallyalong said passage.
 4. A syringe as defined by claim 3 wherein said bodyhas the stop means in communication with said slot and wherein said stopmeans is constructed to provide for a longitudinal insertion of saidstem into said body to obtain the movement of said stop members pastsaid stop means and to inhibit the longitudinal withdrawal of said stemfrom said body to a position where the stop member would be withdrawnpast said stop means.
 5. A syringe as defined by claim 4 wherein saidactuating stem projects from the outer end of said body and has anapertured flange fixed to the outer end thereof and adapted to engage onsaid other end of the body when the stem is fully inserted in the body.6. A syringe as defined by claim 5 wherein said body has an upperportion surrounding a portion of said second passage and having agenerally elliptical transverse curvature in the periphery thereof, saidbody portion also having in the opposite ends thereof external concaverecesses for accomodating the fingers of an operator.
 7. A syringe asdefined by claim 6 wherein said body has a second portion surroundingsaid first passage and having a generally conical cross-section whichconverges from said upper portion towards said one end of the body.
 8. Asyringe as defined by claim 4 wherein said stop member is formed from aresilient material to facilitate the longitudinal movement of the stopmember past said stop means during insertion of the stem into the body.9. A syringe as defined by claim 4 wherein said piston and stemincluding said stop member are integral with each other and formed fromplastic material.
 10. A syringe as defined by claim 4 wherein said stopmeans is formed at the upper edge of said elongated slot.
 11. A syringeas set forth in claim 4 wherein the second passage in the body isenlarged at the end thereof away from the first passage.
 12. A measuringsyringe comprising in combination: a body having a first, narrow,elongated passage in one end thereof extending longitudinally of thebody, a second passage extending longitudinally in the body in alignmentabove said first passage and having a greater cross-dimension than saidfirst passage; a piston assembly including an elongated narrow pistonslidably received in said first passage for drawing and expellingliquid, an actuating stem connected to said piston and slidably receivedin said second passage for operating the piston upon longitudinalmovement of said stem, said actuating stem being dimensioned to beslidably engageable with internal surface portions of said body to beguided thereby during sliding movement of the actuating stem in thebody; stop means formed in said body adjacent said second passage; and astop member projecting laterally from the stem to be engageable withsaid stop means upon withdrawal of the stem to measure a predeterminedamount of said liquid to be drawn and expelLed with the use of thesyringe, said actuating stem projecting from the outer end of said bodyand having an apertured flange fixed to the outer end thereof andadapted to engage on said other end of the body when the stem is fullyinserted in the body, said stop member being formed from a resilientmaterial to enable the stop member to pass said stop mean duringassembly, said stop member having an inclined outer surface slantinginwardly toward the piston end of the stem.
 13. A measuring syringecomprising: a body having a first, narrow, elongated passage in one endthereof extending longitudinally of the body, a second passage extendinglongitudinally in the body above said first passage; a piston assemblyincluding an elongated narrow piston slidably received in said firstpassage for drawing and expelling liquid, an actuating stem connected tosaid piston and slidably received in said second passage for operatingthe piston upon longitudinal movement of the stem; stop means in saidbody adjacent said second passage; and a plurality of stop membersprojecting laterally from the stem at locations spaced axially along thestem to be successively engageable with said stop means upon withdrawalof the stem to measure the amount of liquid drawn into said firstpassage whereby predetermined amounts of liquid may be drawn andsubsequently expelled from said first passage, said stop members madefrom resilient material to enable the stop members to pass said stopmeans, and said stop members having outer surfaces inclined inwardlytowards the piston end of the stem.
 14. A measuring syringe comprisingan elongate body having a first longitudinal passage extending inwardlyfrom one end thereof and a second longitudinal passage of larger crosssection than the first passage in line with the first passage andextending from the inner end of the first passage through the body toits other end with a shoulder at the inner end of the second passagearound the inner end of the first passage, said body having alongitudinal slot in one side thereof opening into said secondlongitudinal passage, an elongate actuating stem having a sliding fit inthe second passage extending out of said other end of said body andhaving means at its outer end enabling it to be manually pulled out, aplunger extending from the inner end of said stem through the firstpassage and having a sliding sealing fit therein, said stem having anintegral stop projecting laterally outwardly into said slot, the stembeing adapted to be pulled out to the limit determined by engagement ofthe stop with the end of the slot toward said other end of the body foran intake stroke of said plunger thereby to prime said first passagewith a measured quantity of liquid, and then pushed in for a dischargestroke of the plunger to the limit determined by engagement of the innerend of the stem with said shoulder.
 15. A measuring syringe as set forthin claim 14 wherein said stem is formed with a plurality of integralstops spaced at intervals along its length, each of the stops beingadapted to be snapped past said other end of the body.
 16. A measuringsyringe comprising: a body having a first, narrow, elongated passage inone end thereof extending longitudinally of the body, a second passageextending longitudinally in the body above said first passage and havinga greater width than said first passage; a piston assembly including anelongated narrow piston slidably received in said first passage fordrawing and expelling liquid, an actuating stem connected to said pistonat one end and slidably received in said second passage for operatingthe piston upon longitudinal movement of the stem; stop means in saidbody at a particular position along said second passage; and a pluralityof stop members projecting laterally from the stem at locations spacedaxially along the stem to be successively engageable with said stopmeans upon withdrawal of the stem to measure the amount of liquid drawninto said first passage whereby predetermined amoUnts of liquid may bedrawn and subsequently expelled from said first passage, the stop meansand the stop member being constructed relative to each other to providefor an insertion of the piston into the body in one direction to obtaina movement of the stop members past the stop means and to inhibit thewithdrawal of the stop members past the stop means in the otherdirection, and wherein said body has an elongated slot in one sidewallthereof communicating with said second passage and extending to saidstop means to provide for the passage of said stop members along saidbody, and wherein said stop members are located in substantially alignedrelationship on the same side of said stop, and wherein the secondpassage in the body is enlarged at the end thereof away from the firstpassage.